Gravitational Definition and 1000 Threads

Alright, so I have a question. Now, on planets such as our Earth, there are a longitude and latitude as well as altitude. If I am not mistaken, I believe the latitude and altitude are part of what affects gravity, or weight, on a planet. Latitude makes it so that the object in question is...

As an object approaches a black hole’s event horizon, it experiences increasing gravitational time dilation, causing it to appear to an outside observer to slow down, until, at the event horizon, it appears to stop. An object traveling in space that increases its velocity from one...

I am reading 't Hooft introduction to general relativity. https://webspace.science.uu.nl/~hooft10 ... l_2010.pdf In this text 't Hoof derives the Rindler transformation. A little bit further he writes My question is, how does he come to that formula $$\rho^{-2}g(\zeta)$$

There is a formula for the potential ##\varphi## outside of a homogenous ellipsoid of density ##\mu## in Landau\begin{align*} \varphi = -\pi \mu abck \int_{\xi}^{\infty} \left(1- \dfrac{x^2}{a^2 + s} + \dfrac{y^2}{b^2 + s} + \dfrac{z^2}{c^2+s} \right) \frac{ds}{R_s} \ \ \ (1) \end{align*}where...

The full title of the publication is: Rare Events Detected with a Bulk Acoustic Wave High Frequency Gravitational Wave Antenna It is published in Physics Review Letters and reported in Phys Org. They have created a small piezo-electric device (< 2cm, though it gets bigger once you create an...

If I'm standing on Earth, is my time dilation actually greater than if I was in a rocket accelerating at 9.8m/s^2 in deep space due to me being in a gravitational field on top of the acceleration? Geodesics experience time dilation in gravitational fields, so it seems like there is an additive...

><br/> >Mass M1 is held on a plane with inclination angle θ, and mass M2 hangs over the side. The two masses are connected by a massless string...

In the screenshots below there are the equations (11.49) and (11.53). I don't understand how did he derive equation (11.53) from Eq.(11.49)? From (11.49) I get: ##d\phi/dy= d\phi/du du/dy = (1/b^2-u^2+2Mu^3)^{-1/2}(1+2My)##. It seems he neglected the ##2Mu^3## since ##Mu\ll 1##, so ##y\approx...

Since an object's apparent mass increases as it approaches the speed of light, does it's gravitational forces also increases? (From a stationary observer's point of view)

I realized I never actually derived the kinematic equations of motion for the exact Newtonian gravitational force. For an object falling near the surface of the earth, how do we handle integrating the equation of motion to derive the kinematics equations without using the approximation of...

It seems like a strong gravitational field acts like spacetime is denser in some sense. Light passing through a gravitational lens is delayed, just like in a glass lens (which refracts because it's denser than air).

Could anyone suggest a simple video showing the Maxwell-Boltzmann distribution under the influence of a gravitational field? I trying to show a flat earther idiot how pressure gradients arise in a simple manner. Thank you all. DF

If the statement above is correct, I do not understand this concept. I guess by charging my phone I am not producing matter. Does it mean in this case, energy converts to mass (not matter)? Can someone please explain this?

I recall some time ago seeing a GR equation describing the rate of orbital energy loss from the moving objects in orbit generating gravitational waves. I can no longer find this equation again. I am hoping someone can help me.

I got (a) but have no idea about b. Potential fields aren't just additive all the time are they?

What is the current scientific consensus on the gravitational force between matter and antimatter. Is it repulsive, attractive or zero?

The exercise is to derive the form of the symmetric, trace-free and transverse gravitational wave perturbation ##\hat{E}_{ij}## to the FRW metric$$ds^2 = a^2(\tau) \left[ -d\tau^2 + (\delta_{ij} + 2\hat{E}_{ij})dx^i dx^j \right]$$First step is to figure out the connection coefficients, which are...

F= Gm1m2/r² = 1.667*10^-7 N. I don't understand How to calculate angular velocity?

Hi, If we are standing on the ground, the Earth applies a force equal to our weight to us, but why do we feel a greater force when we fall to the ground from a certain height? Our weight is the same along this small height because our mass and acceleration are the same and, even so, the normal...

Good day, If I consider my system to be an object and the earth, and the object is on the surface of the earth, then the system will have gravitational potential energy. Why couldn't I say that only the object (considering it as my system) has gravitational potential energy? Thanks

weight/mass = gravitational field strength. my working is -> weight = 150kgx10m/s² = 1500N mass = 150kg gravitational field strength= 10N/kg. is this correct?

A massless scalar field in a curved spacetime propagates as $$(-g)^{-1/2}\partial_\mu(-g)^{1/2}g^{\mu\nu}\partial_\nu \psi=0 .$$ Suppose the gravitational field is weak, and ##g_{\mu\nu}=\eta_{\mu\nu}+\epsilon \gamma_{\mu\nu}## where ##\epsilon## is the perturbation parameter. And let the field...

This question is very confusing since I don't see two distinct particles that are exerting a gravitational force on each other. Also to complicate matters, a gas is made of many individual particles and I don't know how to determine the gravitational force on a single particle from so many other...

First, in section 20.4, after listing all the things gravitational potential energy does not do, they say the equivalence principle forbids it being localized. I thought I understood the equivalence principle, but maybe I don’t. Any comments explaining that would be appreciated. Second, they...

Regarding this paper: https://iopscience.iop.org/article/10.3847/1538-4357/abbb96 In the opening sentence of the Abstract the following is stated: "The strong equivalence principle (SEP) distinguishes general relativity (GR) from other viable theories of gravity. The SEP demands that the...

If we compare 2 scenarios... A) 2 solar mass black hole hyperbolic flyby of Earth at 5000km/s far enough not to cause a tidal disruption event vs B) an extremely close binary pair of 1 solar mass black holes whose barycenter hyperbolically travels past Earth at 5000km/s, also far enough not to...

I am thinking of the mechanism that causes mass-energy to curve spacetime We have the Wheeler (was it ?)description, viz approx "mass tells spacetime how to curve and spacetime tells matter how to move...". Are there any analogous circumstances in other areas of physics where all (or a...

Hello everyone. Probably this question is trivial, but nevertheless I am confused about Newtons law of motion: $$F=G\frac{m_1m_2}{r^2}$$ Now, some sources say, that F is the force between the two masses m1 and m2. Other sources say, that F is the force that m1 exhibits on m2. But isn’t this a...

With regard to relativity of simultaneity and the "block" universe and reflecting on the notion of skewed time slices associated with frames moving relative to each other, one observer sees one event a distance away (parallel to the direction of motion) occurring before another event a distance...

I don't know if this is the ideal sub-forum for this but I'd like to know more about this very recent activity I first saw here >>>>>' It looks like this could be some actually testable, actual breakthrough advances in Physics and the evolution of our Universe. Any comments appreciated.

In https://physicsworld.com/a/physicists-measure-smallest-gravitational-field-yet/ the gravitational constant was measured by the smallest object until now, this is a small golden ball, with a radius of one mm. The intention is to measure some quantum gravitational effects in the future. But, I...

In Box 2.4 of the book "Black Holes & Time Warps" by Kip S. Thorne, he explains gravitational time dilation using the equivalence principle. For this he uses an experiment thought analogous to the one used by Einstein in 1911 to postulate the existence of a gravitational Doppler shift, but...

Suppose some aliens travel to our solar system after seeing our radio broadcasts using an Alcubierre drive. Would it not create a notable gravitational disturbance? Or does it leave spacetime undisturbed around it?

Spacecraft heading to Uranus and Neptune in the next decade could be used to investigate gravitational waves as they venture into the outer Solar System. That is according to a new study by a team of Swiss and Danish researchers, who say that examination of the radio signals from far-flung...

Off the back of a recently closed thread where there was some discussion about the gravitational field of an infinite flat slab, I decided to have a play at investigating that. I've found a few interesting things. It's fairly straightforward to solve for this situation. You use Cartesian-esque...

first to find the force by gravity, it would be 4 kg * 9.8 m/s = 39.2 N then solve for work using W= F*d*cos(theta) W = 39.2 N * 3 m * cos 28 = 103.83 J My confusion is do I use sine or cosine and what angle do I use, the actual angle of the incline or the angle between the mass and the...

Let's assume a binary system with an inclination angle ##i## (angle between the orbital plane and line of sight). Then, according to this source - equations (128) and (129) - for the amplitudes of the tensor polarization modes ("plus": ##+## and "cross": ##\times## polarization) I could write...

It even gives a hint, it says "consider two horizontal surfaces z1 and z2 and think about what thermodynamic equilibrium means for particles traveling from one surface to the other". This really trips me up because I am not sure what to do with this. Obviously in equilibrium the number of...

The faster the relative speed or the more intense the gravitational field, the slower time passes. Does it make sense to ask what both have in common that affects time? Or does the question possibly only make sense in the context of certain theories, for example the LQG, where space and time...

Hi, When regarding Gravitational Potential Energy, I know the formula is U=mgh. However, when the object is on an incline (say at an angle of 52 degrees) would it still be mgh or something else? (This isn't homework I simply was just curious).

hi guys i was reading a book on astrodynamics and was trying to understand the mathematical treatment of the Earth gravitational potential . i kinda understand the main idea , after reaching the following equation of the potential in terms of the Legendre polynomials : ##\alpha = r_{Q}/r##...

The equation of motion for a particle in a gravitational field is ai = -Γijk vj vk In inertial coordinates the Lorentz force is mai = qFij vk So it seems like F corresponds to Γ. Just like F is expressed in terms of the derivatives of A, the christoffel symbols are expressed in terms of...

I'm trying to think of a how the double slit experiment can detect a photon without interacting with it in theory. In principal (not reality of course) does a photon have a gravitational signature which could be used to detect which slit it traveled through during the double slit experiment...

In gravitational lensing, the image magnification is defined as the image area over the source area. But many texts also give it as the inverse of the determinant of the jacobian, A, of the of the lens equation. My question is how these are equivalent. The lens equation is...

https://www.physicsforums.com/threads/what-are-the-best-parameters-for-lcdm.831858/ Hello. In the above linked thread from 2015 Science Advisor Chalnoth replies to Earnest Guest. First, the cosmological constant has been a component of General Relativity pretty much from the start. The way...

I know I just have to replace in the equation, I just want to know, is d=r=0.5 m or is d=2r, so r = 0.25 m ?

I understand that under the GTR space and time are curved and movement takes place along that curved surface. Setting aside for the moment the additional consideration that the space curvature is in three dimensions, I do not understand the impetus for acceleration. If an object is just sitting...

Usually spacetime curvature is localized/proximal to what is "causing" it, right? I'm wondering whether there is a term for the situation seen with gravitational waves where there is some relatively flat space between observable gravitational effects and the mass(es) that "caused" them? I'm...

Hi, I am confused about the negative aspect of these quantities. The definition in my book for gravitational potential is: "The work done to move a unit mass from infinity to a point in a gravitational field" I understand that the work done is negative because gravity is doing the work if you...